# Heat of 30 kcal is supplied to a system and 4200 J of external work is done on the system so that its volume decreases at constant pressure. What is the change in its internal energy ? (J=4200 J/kcal)

47,057 results
1. ## (2-8) Chemistry - Science (Dr. Bob222)

Which of the following statements is correct? A) The internal energy of a system increases when more work is done by the system than the heat that flows into the system. B) The system does work on the surroundings when an ideal gas expands against a

2. ## Honors Chemistry

If 72.4 kJ of heat is supplied to a 752 g block of metal, the temperature of the metal increases by 9.95°C. Calculate the specific heat capacity of the metal in J/g·°C. I cannot find the information in my textbook, and I don't understand the equation

3. ## Physics

A 0.003 0-kg lead bullet is traveling at a speed of 240 m/s when it embeds in a block of ice at 0°C. If all the heat generated goes into melting ice, what quantity of ice is melted? (Lf = 80 kcal/kg, the specific heat of lead = 0.03 kcal/kg×°C, and 1

4. ## Science

In a heat engine, if 700 J of heat enters the system, and the piston does 400 J of work, what is the final internal (thermal) energy of the system if the initial energy is 1,200?

5. ## Physical Science

A heat pump releases 103.0 kcal as it removes 54.0 kcal at the evaporator coils. How much work does this heat pump ideally accomplish? The answer should be in KJ

6. ## Int.Science

How much energy is needed to heat and melt 3.0 kg of copper initially at 83°C? Be mindful of significant figure rules for both multiplication and addition. 450 kcal 430 kcal 280 kcal 130 kcal

7. ## Chemistry

1. A system absorbs 1.57E2 kJ of heat and the surroundings do 1.096E2 kJ of work on the system. What is the change in internal energy (in kJ) (ΔU) of the system? 2. The air in an inflated balloon (the system) absorbs 125 J of heat from its proximity to a

8. ## chemistry

How many calories must be supplied to 59 g of ice at −6 C to melt it and raise the temperature of the water to 61 C? The specific heat of ice is 0.49 kcal/kg · K and of water is 1 kcal/kg · K; the heat of fusion of water is 79.7 kcal/kg, and its heat

9. ## Physics

An electric heater raises the temperature of 120g of water in a thin light vessel through 10K in 2mins, when placed in 70g of water contained in a metal vessel of mass 0.55kg the temperature rises through 9K in the same time. Calculate from the above:

10. ## thermodynamic

When 1.0 mole of liquid Br2 is converted to Br2 vapour at 25.0oC and 1.0 atm pressure, 7.3 Kcal of heat is absorbed, and 0.59 kcal of expansion work is done by the system. Calculate ΔU for this process

11. ## alaqsa

When 1.0 mole of liquid Br2 is converted to Br2 vapour at 25.0oC and 1.0 atm pressure, 7.3 Kcal of heat is absorbed, and 0.59 kcal of expansion work is done by the system. Calculate ΔU for this process

12. ## Physicsl Science

A heat pump releases 103.0 kcal as it removes 54.0 kcal at the evaporator coils. how much work does this heat pump ideally accomplish? Answer should be in KJ

13. ## physics

an electric heater raises the temperature of 120g of water in a thin light vessel through 10K in 2mins, when placed in 70g of water contained in a metal vessel of mass 0.55kg the temperature rises through 9K in the same time. Calculate from the above:

14. ## int.science gtg in 8 min.

How much heat is contained in 100 kg of water at 60.0 °C? Be mindful of significant figure rules for both multiplication and addition. 30 kcal 2.10 x 104 kcal 2.40 x 104 kcal 2.77 x 104 kcal

15. ## Chemistry

-CORRECTION- N2 + O2 --> 2 NO change in heat (delta H)= 43.2 kcal based on the reaction, which statement is true? a) 43.2 kcal are consumed when 1.00g of O2 reacts b) 43.2 kcal are consumed when 1.00g of N2 reacts c) 43.2 kcal are consumed when 1.00g of NO

16. ## Kinesology

A person performs a work task at a mechanical efficiency of 20 percent and at total energy output of 15kcal/min. How much energy(kcal/min) is lost as heat? and how much energy(kcal/min) is used to actually perform the work?

17. ## Chemistry (Food)

The average energy yield per gram of carbohydrate and of fat is A).4 kcal and 9 kcal, respectively B).9 kcal and 4 kcal, respectively C).9 kcal each D).4 kcal each

18. ## Math

The food that the average American consumes in a day provides 2.0 X 10^3 kcal of energy. How many calories a sec is this? *how to set up work in dimensional analysis*? & *what is "k" in kcal stand for*?

19. ## Physics

(a) How much heat in kcal must be provided for a 0.853 kg block of lead to raise the temperature of 0.015 kg block of ice from -5ºC to 0ºC? (b) How much heat in kcal must be provided for a 0.853 kg block of lead to melt a 0.015 kg block of ice from at

20. ## Physics

The figure shows a pV diagram of a gas for a complete cycle. During part bc of the cycle, 1190 J of heat flows into a system, and at the same time the system expands against a constant external pressure of 7.00 × 104 Pa as its volume increases from 0.0200

21. ## Physics

In which of the situations listed below is energy being transferred as heat to the system in order for the system to do work? In which situation is work being done on the system in order for energy to be transferred from the system as heat? a. Two sticks

22. ## Chemistry I

For the methanol combustion reaction 2CH3OH(â„“) + 3O2(g) ----> 2CO2(g) + 4H2O(g) estimate the amount of P [change]V work done and tell whether the work was done on or by the system. Assume a temperature of 27â—¦C. 1. 2.5 kJ, work done by the

23. ## Thermodynamics

in a certain process, 500 cal of heat are supplied to a system, and at the same time 100 joules of work are done. what is the increase in the internal energy of the system

24. ## PHYSICS HELP

If the external world does work on the system, the quantity of work is negative. Is negative right or is it positive? If you are writing the system equations, the work done by external forces will be a + number, indicating an increase of energy to the

25. ## Chemistry

Chemistry question: Given: CH4 + 2O2 ~ CO2 + 2H2O C - H = 99 kcal O - O = 119 kcal C = O = 192 kcal O - H = 111 kcal Calculate the change in energy for the CH4 - O2 system.

26. ## Science

A person performs a work task at a mechanical efficiency of 20 percent and at total energy output of 15kcal/min. How much energy(kcal/min) is lost as heat? and how much energy(kcal/min) is used to actually perform the work?

27. ## Science - Melting Ice

In the process of heating ice into the boiling state of its liquid form, did the procass absorb or release energy? Did the molecules spontaneously move fast? Where did the energy come from and where did it go? did it increase or decrease? was it lost? Were

28. ## Chemistry 2

Potassium nitrate has a lattice energy of -163.8 kcal/mol and a heat of hydration of -155.5 kcal/mol. How much potassium nitrate has to dissolve in water to absorb 107 kJ of heat?

29. ## physics

A system undergoes a two-step process. In the first step, the internal energy of the system increases by 368 J when 144 J of work is done on the system. In the second step, the internal energy of the system increases by 24 J when 248 J of work is done on

30. ## chemistry

The heat of vaporization of water is 40 kJ mol-1 at 100oC. What percentage of the heat supplied to vaporize the water can be converted into work if the water is vaporized at 100 degrees C against a constant pressure of 1 atm?

31. ## Physics

We have a heat engine that produces 150 J of heat, does 40 J of work, and emits 110 J into another system. What is the efficiency of the heat engine? (show you work)

32. ## Physics

Heat of 30 kcal is supplied to a system and 4200 J of external work is done on the system so that its volume decreases at constant pressure. What is the change in its internal energy ? (J=4200 J/kcal)

33. ## Physics

Heat of 30 kcal is supplied to a system and 4200j of external work is done on the system so that it's volume decreases at constant pressure.what is the change in its internal energy (J=4200 j/kcal)

34. ## chemistry

N2 + O2 --> 2 NO change in heat (delta H)= 43.2 kcal based on the reaction, which statement is true? a) 43.2 kcal are consumed when 1.00g of O2 reacts b) 43.2 kcal are consumed when 1.00g of N2 reacts c) 43.2 kcal are consumed when 1.00g of NO is produced

35. ## physical science

Lead is a soft, dense metal with a specific heat of 0.028 kcal/kg·C°, a melting point of 328.0°C, and a heat of fusion of 5.5 kcal/kg. How much heat must be provided to melt a 202.2 kg sample of lead with a temperature of 20.0°C?

36. ## Chemistry

Hi! I have another question. So 1 kcal of heat is added to 1.5 L of oxygen in a container at constant pressure. (1atm). Then volume increases to 3.1L. they want to know total energy change. Now i think the formula is DH=DU + PDV so what i did was DH = 1

37. ## physics

A copper calorimeter of mass ()g contains 380g of a liquid at 12degrees Celsius. A 20W heater is used for 3 minutes to raise the temperature of the liquid and calorimeter to 17 degrees Celsius. The calorimeter has a specific heat capacity of 400 J/K kg

38. ## sc

The specific heat of concrete is 0.16 kcal/kgC o , and the specific heat of water is 1.00 kcal/kgC o . This means that if 1 kg of ice and 1 kg of water each receives 1 kcal of energy

39. ## chem

Tin and Chlorine synthesize Stannous Chloride according to a two step mechanism: Sn (s) + Cl2 (g) ⇌ SnCl2 (s) + 83.6 kcal SnCl2 (s) + Cl2 (g) ⇌ SnCl4 (l) + 46.7 kcal Determine the overall heat of reaction and write the final equation for the reaction.

40. ## chemistry help!

Potassium nitrate has a lattice energy of -163.8 kcal/mol and a heat of hydration of -155.5 kcal/mol. How much potassium nitrate has to dissolve in water to absorb 105 kJ of heat?

41. ## physic

A 2000 kg car is traveling at 20.0 m/s. Then, it puts on the brakes and comes to a complete stop. The heat generated due to the stopping heats up the brakes. The mass of the brake system is 20.0 kg and it has a specific heat of 0.200 kcal/kg °C. What is

42. ## Physics

Just as no mechanical device can be 100% efficient, no heat engine can transfer 100% of its heat to a single object. Some of the heat energy must be wasted (released into the environment). We have a heat engine that produces 150 J of heat, does 40 J of

43. ## College Chemistry

1. What is the change in internal energy (in J) of a system that absorbs 0.677 kJ of heat from its surroundings and has 0.438 kcal of work done on it? 2. A 30.5 g sample of an alloy at 94.0°C is placed into 48.7 g water at 20.3°C in an insulated coffee

44. ## Chemistry

How do I determine the value of the reaction 2HI(g) + 2.4 kcal --> H2(g) + i2(g) delta H = a) 2.4 kcal b) -2.4 kcal c) 0.00024 kcal d) -0.00024 kcal

45. ## physics

How many joules of energy are required to heat 2 L of water from 25 C to 100 C? I looked up that the specific heat is 4200 J/kgK and i keep getting Q to equal 630000 but my homework website says that's wrong.

46. ## physics

a .250kg block of aluminum is heated to 100 C and then dropped into .60 kg of water that is initially at 20C. What is the equilibrium temperature of the system? The specific heat of aluminum is .22 kcal/kg C

47. ## Science

In a heat engine, if 700 J of heat enters the system, and the piston does 400 J of work, what is the final internal (thermal) energy of the system if the initial energy is 1,200 J?

48. ## chemistry

What is the change in internal energy (in J) of a system that absorbs 0.246 kJ of heat from its surroundings and has 0.771 kcal of work done on it? Is this correct? 0.246, kJ x (1000 J/1 kJ) = 246 J 0.771 kcal x (4184 J/1 kcal) =3225.86 j 246 J + 3225.86 J

49. ## Physics

In a certain process, 2.11x10^5 J of heat are supplied to a system and at the same time, the system expands against a constant external pressure of 6.89x10^5 Pa. Given that the temperature of the system does not change, find the increase in volume of the

50. ## Physics / Heat Transfer

How much heat must be removed from a 200 g block of copper to lower its temperature from 302 oF to 68 oF? Specific heat of copper: c = 0.092 kcal/(kg K) a. 2.4 kcal b. 2400 kcal c. 18.4 kcal d. 12 kcal e. 26 kcal

51. ## physics

An electric heater raises the temperature of 120g of water in a thin light vessel through 10K in 2mins, when placed in 70g of water contained in a metal vessel of mass 0.55kg the temperature rises through 9K in the same time. Calculate from the above:

52. ## chemistry

A system performs 120J work with no heat supplied to it. Calculate the change in internal energy of the system.

53. ## PHYSICS HELP

I am having a real problem with this question. Through the process of doing work, energy can move between the external world and the system as the result of forces or work. I say it's forces, but someone else says it's work because only work and energy can

54. ## Chemistry

If a system has 2.50 × 102 kcal of work done to it, and releases 5.00 × 102 kJ of heat into its surroundings, what is the change in internal energy of the system?

55. ## physics

A 0.250-kg aluminum bowl holding 0.800 kg of soup at 27.0°C is placed in a freezer. What is the final temperature if 430 kJ of energy is transferred from the bowl and soup? Assume the soup has the same thermal properties as that of water, the specific

56. ## Chemistry

What is the change in internal energy (in J) of a system that absorbs 0.677 kJ of heat from its surroundings and has 0.438 kcal of work done on it?

57. ## Chemistry

What is the change in internal energy (in J) of a system that absorbs 0.677 kJ of heat from its surroundings and has 0.438 kcal of work done on it?

58. ## Chemistry

What is the change in internal energy (in J) of a system that absorbs 0.677 kJ of heat from its surroundings and has 0.438 kcal of work done on it?

59. ## Physics

A heat engine absorbs 126 kcal of heat and exhausts 77 kcal of heat in each cycle. Calculate the efficiency (as a percentage)

60. ## Physics

A heat engine absorbs 126 kcal of heat and exhausts 77 kcal of heat in each cycle. Calculate the efficiency (as a percentage)

61. ## Physics

A heat engine absorbs 126 kcal of heat and exhausts 77 kcal of heat in each cycle. Calculate the efficiency (as a percentage)

62. ## Chemistry

Given: CH4 + 2O2 ~ CO2 + 2H2O C - H = 99 kcal O - O = 119 kcal C = O = 192 kcal O - H = 111 kcal Calculate the change in energy for the CH4 - O2 system.

63. ## physics

The internal energy of a system changes because the system gains 180 J of heat and performs 338 J of work. In returning to its initial state, the system loses 111 J of heat. During this return process, what work is involved? If the work is done by the

64. ## Physics

If ∆Q is the heat supplied to a gas so that the internal energy of the system increases by ∆U, then the work done ∆W by the gas is equal to: ∆Q – ∆U ∆Q + ∆U ∆Q x ∆U ∆U/∆Q

65. ## Chemistry

A system has an initial energy of 117 joules. The energy equation includes --40.1 J of heat and -20.3 J of work. What is the final energy? Was heat added to the system or to the environment? Was work done by the system or to the system? Be sure to show all

66. ## Physics

If the heat of 110J is added to a gaseous system, change in internal energy is 40J, then the amount of external work done is?

67. ## physcial science

When 1 kg of ice at 0 degrees Celsius absorbs 80 kilocalories of heat, the ice undergoes a) a change of state b) a loss of energy c) a rise in temperature d) an increase in volulme The heat of fusion of water is 80 kcal/kg. That means that 1 kg of ice will

68. ## Chemistry

Hi! I have another question. So 1 kcal of heat is added to 1.5 L of oxygen in a container at constant pressure. (1atm). Then volume increases to 3.1L. they want to know total energy change. Now i think the formula is DH=DU + PDV so what i did was DH = 1

69. ## Chemistry

Hi! I have another question. So 1 kcal of heat is added to 1.5 L of oxygen in a container at constant pressure. (1atm). Then volume increases to 3.1L. they want to know total energy change. Now i think the formula is DH=DU + PDV so what i did was DH = 1

70. ## Physics

How much (in Celsius degrees) is the temperature of 1.3 kg of alcohol raised by adding 4.1 kcal of heat? The following piece of information may come in handy: specific heat of alcohol is 0.58 kcal/kgC.

71. ## Physics

How much (in Celsius degrees) is the temperature of 1.3 kg of alcohol raised by adding 4.1 kcal of heat? The following piece of information may come in handy: specific heat of alcohol is 0.58 kcal/kgC.

72. ## Physics

How much (in Celsius degrees) is the temperature of 1.3 kg of alcohol raised by adding 4.1 kcal of heat? The following piece of information may come in handy: specific heat of alcohol is 0.58 kcal/kgC.

73. ## physics

lead is a soft, dense metal with a specific heat of 0.028 kcal/kg degrees C, a melting point of 328.0 degrees C and a heat of fusion of 5.5 kcal/kg. How much heat must be provided to melt a 250.0 kg sample of lead with a temperature of 20.0 degrees

a. Two sticks are rubbed together to start a fire. b. A firecracker explodes. c. A red-hot iron bar is set aside to cool. In which of the situations listed above is energy being transferred as heat to the system in order for the system to do work? I would

75. ## chemistry

Potassium has a lattice energy of -163.8 kcal/mol and a heat of hydration of -155.5 kcal/mol. How much potassium nitrate needs to dissolve in water to absorb 114 kJ of heat?

76. ## chemistry

Potassium has a lattice energy of -163.8 kcal/mol and a heat of hydration of -155.5 kcal/mol. How much potassium nitrate needs to dissolve in water to absorb 114 kJ of heat?

77. ## Chemistry

Gasoline, which can be represented by the formula octane, bulk density is 704 g / l. To estimate the variation in enthalpy when burning 28.5 liters gasoline, based on the binding energies: 0 = 0 (117 kcal); C = 0 (173 kcal); 0 h (111 kcal); C-C (83 kcal);

78. ## Chemistry

Gasoline, which can be represented by the formula octane, bulk density is 704 g/l. To estimate the variation in enthalpy when burning 28.5 liters gasoline, based on the binding energies: 0 = 0 (117 kcal); C = 0 (173 kcal); 0 h (111 kcal); C-C (83 kcal);

79. ## Chemistry

Gasoline, which can be represented by the formula octane, bulk density is 704 g/l. To estimate the variation in enthalpy when burning 28.5 liters gasoline, based on the binding energies: 0 = 0 (117 kcal); C = 0 (173 kcal); 0 h (111 kcal); C-C (83 kcal);

80. ## Chemistry

The petrol, can be represented by the formula of the octane rating, has earth specifies 704 g/L. Estimate the enthalpy variation when burning 28.5 liters of petrol, assuming energies of connection 0 = 0 (117 kcal) C = 0 (173 kcal) 0–H (111 kcal) C–C

81. ## chemistry

S8 (rhombic) + 12 O2 (g)-----> 8 SO3 (g) + 752.0 kcal In the reaction above equated, performed at 25 °c and 1 atm, the formation enthalpy of the SO3 (g) is equal to: a) +752,0 kcal b) -752,0 kcal c) +773,0 kcal d) -94,0 kcal e) +94,0 kcal

82. ## physics

which is false? Consider the following processes: I. Energy flows as heat from a hot object to a colder object II. Work is done on a system and an equivalent amount of energy is rejected as heat by the system III. Energy is absorbed as heat by a system and

83. ## Chemistry

Water freezes completely at 0.00° C, giving off 12.0 kcal of heat. What is the mass of the water? (heat of fusion (∆Hf) = 80.0 cal/g) Please show work

84. ## Nsuk

(1)calculate the heat energy datas temperatures 100degree celciuse and 4degree celciuse,mass 0.5kg take latent heat of vapourisation 2.02times10raised to the power of minus6.(2)calculate the specific latent heat of fusion mass of calorimeter 0.01kg and

85. ## chem

The heat of combustion of methane is 213 kcal/mol. How many kcal of energy are released when 22.5 moles of CH4 burns in an excess of oxygen gas?

86. ## Physics, help!

A heat engine absorbs 126 kcal of heat and exhausts 77 kcal of heat in each cycle. Calculate the efficiency (as a percentage) An ideal gas heat engine operates in a Carnot Cycle between temperatures of 266 and 115°C. It absorbs 4250 cal per cycle at

87. ## physics- response to bobpursley

which is false? Consider the following processes: I. Energy flows as heat from a hot object to a colder object II. Work is done on a system and an equivalent amount of energy is rejected as heat by the system III. Energy is absorbed as heat by a system and

88. ## chem

Potassium nitrate has a lattice energy of -163.8 kcal/ mol and a heat of hydration of -155.5 kcal/ mol . How much potassium nitrate has to dissolve in water to absorb 105kj of heat? Answer in kg.

89. ## chemistry

Potassium nitrate has a lattice energy of -163.8 kcal/mol and a heat of hydration of -155.5 kcal/mol. How much potassium nitrate has to dissolve in water to absorb 114 kj of heat?

90. ## Science

Consider the isothermal expansion of 4.50 mol of an ideal gas at 450 K from an initial pressure of 12.0 bar to a final pressure of 2.75 bar. Describe the process that will result in the greatest amount of work being done by the system and calculate work

91. ## chemistry

if change in E= -1500J what does that mean? the system gained heat the surroundings lost heat the system did work the surroundings did work more information is needed please help.

92. ## Chemistry

Calculate the energy required to produce 5.00 mol of Cl2O7 on the bases of the following balanced equation. 2Cl2(g) +7O2(g) +130kcal - - > 2 Cl2O7 5.00 kcal 65 kcal*** 130 kcal 325 kcal

93. ## abiapoly heat energy

500g of copper is heated from 30 degree celcius to 120 degree celcius what is the quantity of heat supplied b.if the same quantity of heat is supplied to 300g of water initial at 30degree what will be the final temperature?

94. ## Chemistry

How do I determine the value of the reaction 2HI(g) + 2.4 kcal --> H2(g) + i2(g) delta H = a) 2.4 kcal b) -2.4 kcal c) 0.00024 kcal d) -0.00024 kcal

95. ## ap chemistry

a system undergoes a process consisting of the following two steps: step 1: the system absorbs 72 J of heat while 35 J of work is done on it. step 2: the system absorbs 35 J of heat while performing 72 J of work calculate delta E for the overall process.

96. ## Heat Transfer

A metal storage tank of external area 0.5 m^2 contains water at 65 degree C. & is located inside a large enclosure with wall at 10 deg.C. the tank is painted black on the outside & its emissivity is approx. to 0.95. How much reduction in heat loss would

97. ## chemistry

Hi, I'm doing a post-lab report and I have no idea how to solve this question. It asks which of the following molecules would be useful in quenching benzophenone photoreduction. it then lists oxygen (s1 = 22kcal/mol), 9,10-diphenylanthracene (t1=42

98. ## physics

during a process, 21.6 MJ of heat is added to closed system. if the internal energy is increased by 59.6 MJ, how much work in Btu was done? is the work done on ro by the system?

99. ## phyics

during a process, 21.6 MJ of heat is added to closed system. if the internal energy is increased by 59.6 MJ, how much work in Btu was done? is the work done on ro by the system?

100. ## Heat energy

CORRECTION (a). 500g of copper is heated from 30 degree celcius to 120 degree celcius, what is the quantity of heat supplied?(b). If the same quantity of heat is supplied to 300g of water initial at 30 degree celcius. What will be the final temperature.